Substitute 50 Ghz Sweeper For 20 GHz Sweeper

I have a 8510C that we are using for 110 - 220 GHz measurements. The LO (26.5 GHz) 83630 is having some issues, complains about overmodulation errors and fails the self test noting an X10 amplifier problem. I was hoping I could take a extra 83650 50 GHz sweeper and use it in it's place. Is this possible? Thanks!